As you see, I pretty much got wide and zoom sides covered. But the "walkaround" range has some gaps. 17-35 sometimes just doesn't have enough reach. 50 is a good prime, but no zoom/flexibility. What should I do?

Tamron 24-70 gets pretty good reviews. How about Sigma 17-85?? Canon 24-105L or the new Canon 17-55 2.8IS are expensive options. Any thoughts?